Impulse circuit



Jan? 5, 1932. g sg 1,840,097

IMPULSE CIRCUIT Filed July 31, 1950 N V5. N TC] F? E. E. H/NR/CHSEN ATTORNEY such as the selector S having the brushes 20, 21 and 22. As soon as the subscribers line is extended to the selector S, a circuit is closed for the impulse relay 9 and may be traced from battery through the lower winding of said relay, lowermost contact of relay 15, over the ring conductor 8, brush 4, thence over the loop of the calling line and returning through brush 3 and tip conductor 7 uppermost back contact of relay 15, upper winding of relay 9 to ground. The impulse relay 9 attracts its armature and closes an initial energizing circuit for the holding relay 10. This circuit may be traced from battery through the winding of relay 10, front contact of relay 9 to ground through the inner lower contact of relay 15. The holding relay 10, which controls the release of the switch, is designed with a slow-release characteristic in order that it will maintain its armatures in their attracted position during the intervals that it is deprived of energizing current while the impulses are being received.

The calling subscriber now manipulates his impulse transmitter 2 to send a series of impulses representing a digital place in the wanted-designation. On thefirst opening of the subscribers line by the impulse transmitter 2, the impulse relay 9 releases its armature, first opening its front contact and immediately thereafter closing its back contact. The opening of the front contact of the relay 9 opens the energizing circuit of the holding relay and this relay commences to lose energy.

However, due to its slow-release characteristie, it will retain its armaturcs. Relay 9 at its back contact closes a circuit for delivering the first impulse to the vertical stepping magnet '12, 'This circuit may be traced from ground throughthe inner lower contact of relay 15, 'back contact of relay 9, right-hand armature and front contact of relay 10, winding of the change-over relay 11, winding of the vertical magnet 12 to battery. The relay 11, which immediately operates in this circuit, is also constructed with a slow-release characteristic inorder that it will retain its armatures attracted during brief interruptions of its energizing circuit. The vertical magnet 12 responds to current flowing in this circuit and steps'the brushes 20, 21 and 22 one vertical step to position them opposite the first level of contacts'in the switch.

The vertical ofl -normal contact 16 is closed on the "first vertical step of the switch and completes a circuit for the relay 14. This circuit extends from battery through the winding of the relay, contact of the rotary stepping magnet 13, off-normal contact 16,

'upper frontcontact of the relay 11, conductor .24'to ground at the left contact of relay 10. Relay 14 operatesand locks in a circuit from battery through its winding, contact of the stepping magnet 13', contact 16, left front contact of relay 14, to the grounded conductor 24.

At the end of the first impulse, the transmitter 2 recloses the line, and the relay 9 attracts its armature, opening the stepping circuit and permitting the vertical magnet 12 to release. Relay 9 at its front contact recloses the initial energizing circuit of the holding relay 10, and this relay commences toregain its lost energy. On each of the following impulses, relay 9 retracts its armature and recloses the energizing circuit of the vertical magnet 12, and this magnet advances the switchto the next succeeding level.

. In addition to its-initial energizing circuit, the relay 10 is also provided with an auxiliary holding circuit which may be traced from battery to the winding of the relay, lower front contact'of relay ll, normally closed contact of the vertical magnet 12, rotary off-normal contact 17,which does not open until the switch begins its rotaryv movement, conductor 24 to ground at the left contact ofyrelay 10. Inasmuch as the relay 11 remains energized continuously throughoutthe impulse series,

the auxiliary circuit is not opcned'at the lower contact of this relay. The auxiliary circuit is, however, opened once for each impulse at the normally closed cont-acts of the magnet 12. Sincethe energizing circuit of the magnet is not'closed-until' the armature of relay 9 has closed its back contact and since the contacts on the magnet 12may be adjusted to open only'after the magnet has, substantially completed its vertical stroke, it follows that the auxiliary circuitof-the-relay 10 is maintained closed for a considerable time after the initial energizing circuit of said relay opened at the front contact of relay 9. Consequently, the relay 10 retains :most of its 11" energy, and, its circuit closes during eachimpulse for a sufiicienttime to enable it to re gain all the energy that it has lost during the brief open period.

At the end of the impulse series, the line is 1. l

reclosed for alonger intervahand relay 9 attracts and holds its armature against its front contact. After an interval, relay ,1 1' releases its armatures and in so doing prepares an energizing circuit for the rotary magnet 13 to advance the brushes 20, 2l and 22 over the contacts of the selected group. The circuit for magnet 13 may be traced from battery throughthe winding of the magnet, right contact of relay 14, normal 2;-

contacts of relay llto the grounded conductor 24. The magnet 13 energizes and steps the brushes onto the first set of contacts in the group. Magnet 13 also attracts its armature, and opens the holding circuit of relay L"? 14. Relay 14 immediately releases and opens the energizing circuit of the magnet 13, whereupon. the magnet releases preparatory to taking the next step. If the circuit 23 appearing in the first set of contacts is busy, 15;;

1 the test brush -22 encounters a ground 'poten which releases its armature.

tial on the test terminal, and the relay 14 is reenergized in the following circuit battery,

through the winding of said relay, contact of the magnet 13, contact '16, inner upper back contact of relay 15, brush 22 to the grounded terminal. A parallel circuit may be traced from battery throughthe' winding of relay 14, contact of themagnet- 18, contact 16, Winding of switching rela'y15 to the grounded conductor 24. Since there is a direct ground potential on the brush 20, relay is shunted anddoes not operate Relay 14 in operating reclo'ses the circuit of the magnet 13,which advances the'brushes another step and opens the circuitot relay 14. Relay 14 releases and releases the magnet 13. This action continues until the test brush 22 encounters an idle terminal, whichis represented by the absence of ground potential. At this time the shunt is removed from the winding of relay 15 and the relay immediately energizes. Relay 14, however, does not energize in this circuit due to the resistanceot the relay 15. Accordingly, the circuit of the stepping magnet 13 is maintained open and the switch ceases to advance, coming to rest on the terminals of the idle circuit. f

The relay'15 in operating switches the tipand ring conductors of the circuit through the brushes and 21 and thence to the next succeeding switch. Relay 15 by'attracting its armatures opens the circuit, of relay 9 After an interval the relay 1O releases since both its initial circuit and auxiliary holding circuit are now open. Before relay 10 can release to remove ground from conductor 24, ground.

potential will have been substituted onthis conductor from the succeeding switch over a.

circuit extending throughthe brush 20 and the upper inner armature and front contact of relay 15. This substitute holding ground may serve to maintain the line finder F and alsoto hold the relay 15 energized.

\Vhen it is desired to release the selector S, ground potential is removed from the conductor 24, thereby permitting the release of relay 15. Relay 15 closes an energizing circuit for the release magnet 18, traceable from battery through the win-ding of said magnet, vertical oft-normal contact 19, right back contact of relay 10, back contact of relay 9, to ground through the inner lower contact of relay 15. The release magnet 18 energizes and releases the switch S. When switch S fully restores, the vertical oil-normal contact 19 is opened and the magnet 18 deenergizes.

The relay 10 is permitted to release after the switch has completed its functions since, as above noted, its initial energizing circuit is opened by the relay 9 and its auxiliary circuit has already been opened at the contact of relay 11.

Should the subscriber abandon the call before transmitting impulses to the switch, relay 9 in releasing would close the previously traced energizing circuit for the magnet 12, and the magnet on energizing would. open the auxiliary circuit of relay 1O permitting this relay to release aft-er an interval. Should the subscriber abandon'the call during the rotary movement of the switch,the*'release of relay 10 is insured by the rotary off-normal contact 17. v The release of relay 9 under such condition closes all energizing circuit for the vertical magnet 12, but, since the switch has commenced rotary movement, magnet 12 is unable to advance: its stepping dog a full step, and, according to the adjustment of the .arinatureon the magnet, its contact might not open. :l-low'ever, the auxiliary holding circuit of the relay 10 has already beenopencd at the contact 17, and,

therefore, the relay is permitted to release.

If it were desired to dispense with the contact 17, the vertical magnet might be so ads justed that it would open'its left contact on a short stroke of its stepping. dog. 1 r g a i Fig. 2 illustrates a modification of the invention. In this figure the auxiliary holding that relay 14'energizes on the first vertical step of the switch and remains energized during the vertical movement. Therefore,

the auxiliary circuit of relay 10; remains closcdat the contact of relay 14 during the vertical movement of the switch and, is

opened successively at the contact of the vertical magnet 12 above described. During the. secondary or rotary movement of the switch the relay 14 operates and releases successively :to control the rotary magnet 13. These brief interruptions of the auxiliary circuit of relay 14 do not interfere with the relay 10 since this relay is now held over its initial energizing circuit through the front contact of relay 9. At the. end of the rotary movement, relay 9 deenergizes and relay 14 remains deenergizedto permit the release of relay 10.- I a r a v p The finder Fahd the selector switch S disiclosedin this applicatiou may bev of any suitable construction] The selector S is preterably of the two-movement step-by-step type havinga first stepping movement to select groups of trunks or lines and a second stepping movement to select individual trunks or lines. A switch of this character is described in the patent to Keith et al. No. 815,176, granted March 13, 1906.

lVhile' the invention has been illustrated in connection with'a specific circuit arra nge'-- ment, it is to be understood that it is not limited to these particular circuits. It should also be not-ed that this invention is applicable to repeatersused tor repeating-impulses from an incoming circuit to, an outgomg circuitand that it is also applicable to connector switches in which both the primary and secondary movements are directively controlled by impulses.

What is claimed is:

1. The combination in an impulse circuit of an impulse relay, a stepping magnet, means controlled by said relay for delivering impulses to said stepping magnet, a holding relay, a circuit for the winding of said holding relay closed at the front contact of said impulse relay, and a second circuit for said winding controlled by said stepping magnet.

2. The combination in an impulse circuit of an impulse relay, means for sending impulses to cause the successive operation and release of said relay, an operating device having contacts which open when the device is energized, a second relay having a winding and a circuit for said winding closed at the front contact of said impulse rela a circuit controlled by said impulse relay or delivering operating impulses to said operating device, and a second circuit for said winding extending through the contacts of said operating device.

3. The combination in an impulse circuit of an impulse relay, a magnet, a circuit controlled by said relay for delivering o erating impulses to said magnet, a second re ay having a single winding therefor, a circuit for said winding closed by said impulse relay, an auxiliary circuit for said winding controlled by said magnet, and a releasing device controlled by said second relay.

4. In combination, an impulse relay, a stepping magnet, a circuit controlled by said impulse relay for delivering impulses to operate said magnet, a relay having its winding t in said circuit, a holding relay having a circuit closed by said impulse relay, and a second circuit for said holding relay controlled by said magnet and by said second-mentioned rela 5. The combination in a selective switch having primary and secondary movements of an impulse relay, a magnet for operating said switch in its primary movement, a circuit controlled by said relay for sending impulses to operate said magnet, a second rela-y having a circuit closed by said impulse relay, an auxiliary circuit for said second relay controlled by contacts on said magnet, and a contact operated by said switch in its secondary movement for controlling said auxilia-ry circuit.

6. The combination in an impulse circuit of an impulse relay, a stepping magnet, a

. circuit controlled by a back contact of said relay, and another circuit for said winding oontrolledata back contact of said steppilfii magnet.

7. The combination in an impulse circuit of an impulse relay, a magnet, a circuit con- 

